Sunday 23 March 2014 16.06 EDT
First published on Sunday 23 March 2014 13.38 EDT

Investigators looking for the missing Malaysia Airlines plane struggled on Sunday to locate several pieces of potential debris spotted separately by an aircraft and three satellites, as bad weather continued to hinder the vast international search mission.

New images produced by a French satellite showed “potential objects” related to flight MH370 in the southern Indian Ocean, the Malaysian transport ministry said in a statement. “Malaysia immediately relayed these images to the Australian rescue co-ordination centre,” it added.

The new satellite image lead came after the crew of a civilian search aircraft reported seeing a wooden pallet and strapping belts during a fly-over, and Chinese officials on Saturday unveiled the second potential satellite sighting after an Australian announcement late last week.

The Australian prime minister, Tony Abbott, said on Sunday that while the findings were “credible leads” for those searching the so-called southern corridor identified by authorities as the plane’s likeliest destination, they offered “no more than hope” at this stage.

“It is still too early to be definite, but obviously we have now had a number of very credible leads, and there is increasing hope, no more than hope … that we might be on the road to discovering what did happen to the aircraft,” Abbott said, at a press conference in Papua New Guinea.

Poor weather conditions, in some of the most inhospitable seas on Earth, have further complicated the search mission and will make the job of observers on the search vessels more difficult.

Sunday's search was frustrating because “there was cloud down to the surface and at times we were completely enclosed by cloud”, Flight Lieutenant Russell Adams of the Royal Australian Air Force told the Associated Press at the base in Perth for planes working for the search mission.

Commander William Marks of the US Navy’s Seventh Fleet, which is leading the American side of the search party, also stressed that the region of the ocean being searched remained vast.

“I can tell you that we are looking in something like the area between New York and California,” he told ABC News, “and we just don't know where we should look.”

A Malaysian official involved in the search mission was reported to have told the Associated Press that the objects spotted by the French satellite were about 930km (575 miles) north of those previously detected by China and Australia.

As the search continues, the families of the 239 people who were on board the plane when it went missing more than two weeks ago have expressed growing frustration at the progress of the search and the contradictory information released by the Malaysian government. In Beijing on Saturday, relatives were prevented by police from confronting Malaysian officials after a heated exchange at a daily news briefing.

A US congressman on Sunday became the most senior American public figure to criticise the Malaysian government’s handling of the crisis, urging authorities there to be more transparent with what they know and to share information more promptly.

"I wish it was better," Patrick Meehan, a Pennsylvania Republican who chairs the counter-terrorism and intelligence subcommittee of the House of Representatives homeland security committee, told CNN on Sunday, following reports of Chinese discontent about Malaysian co-operation.

"The reports that I'm getting are of frustration. We're invited in only a little bit. We have legats [legal attaches] there from the FBI and State Department, very small to the extent that we are asked. And there is concern.

Meehan went on: "I think across the board people are looking for more in the way of openness from the Malaysian government in terms of sharing the information they have in a timely manner."

The Malaysian transport ministry also said in its statement that the plane was still on course to Beijing when the last data was sent from its Acars (Aircraft Communications Addressing and Reporting System) at 1.07am. US officials last week briefed The New York Times that the route was reprogrammed before the Acars was shut down – further raising suspicions about the pilot and first officer.

“During Saturday’s search activities the crew of a civil aircraft sent out by Amsa reported sighting a number of small objects with the naked eye, including a wooden pallet, within a radius of five kilometres,” the statement said. The crew were unable to photograph the object.

In a briefing on Sunday, Mike Barton, Amsa's rescue coordination centre chief, said: “The use of wooden pallets is quite common in the industry … They're usually packed into another container, which is loaded in the belly of the aircraft.”

Barton also said that the possible debris seen by the search aircraft also included "strapping belts of different lengths". Barton said a “methodical search” of the area was under way but that it “continues to change as the water movements change.”

Abbott announced on Thursday that a first “credible” sighting had been made in the Indian Ocean, about 2,500km south-west of Perth, based on satellite imagery of two large objects.

The series of announcements has seen a major concentration of effort to scour the southern Indian Ocean for the missing Boeing 777-200, which went missing after taking off from Kuala Lumpur bound for Beijing.

Malaysian authorities have said that they believe the plane was deliberately rerouted. Electronic signals sent from its engines are said to have indicated that it continued flying for more than six hours after it lost contact with the ground when two communications systems were shut down, about 40 minutes into the journey.

Eight aircraft have been tasked by Amsa to undertake the search and vessels from the US, New Zealand, China and Japan are also aiding in the operation.

A senior aide to President Barack Obama stressed on Sunday that the US government had no extra information about the fate of the plane that it was holding back from the public.

"We do not know yet what happened to the plane, and why it happened," Tony Blinken, Obama's deputy national security adviser, told CNN. "Publicly or privately, we don't know.”

Satellite and meteorology experts have expressed doubts about the prospect of finding the objects in the Indian Ocean believed to be linked to the missing flight, flagging the possibility that the debris could have drifted hundreds of miles since it was first detected, due to strong currents.

The search area for Sunday has been split into two areas, to account for the possible drifts.